1. Field of the Invention
The invention relates to a variable valve timing device for an internal combustion engine, which includes a variable valve timing mechanism that changes the valve timing of at least one of an intake valve and an exhaust valve that serve as engine valves and a phase limiting mechanism that locks a relative rotational phase between an input rotor and an output rotor that constitute the variable valve timing mechanism at a specific phase, and a manufacturing method for the variable valve timing device.
2. Description of Related Art
The variable valve timing device is, for example, known as the one described in Japanese Patent Application Publication No. 2002-357105 (JP-A-2002-357105). A phase limiting mechanism of the variable valve timing device includes an advance limiting mechanism and a retard limiting mechanism. The advance limiting mechanism limits a change of the relative rotational phase of an output rotor with respect to an input rotor toward an advance side with respect at a specific phase. The retard limiting mechanism limits a change of the rotational phase toward a retard side with respect to the specific phase. In addition, the phase limiting mechanism includes a locking mechanism that locks the relative rotational phase of the output rotor with respect to the input rotor at the specific phase. The locking mechanism engages an engaging element provided for the output rotor with an engaging hole provided for the input rotor to lock the relative rotational phase between the output rotor and the input rotor.
Incidentally, other than the above locking mechanism, a mechanism that locks the output rotor at a specific phase with respect to the input rotor as described above is conceivably configured to lock the input rotor and the output rotor at a specific phase by the cooperation of the advance limiting mechanism and the retard limiting mechanism. Specifically, when the relative rotational phase of the output rotor with respect to the input rotor is a specific phase, the engaging element of the advance limiting mechanism contacts an advance-side engaging portion of an engaging groove to limit advance of the relative rotational phase, and the engaging element of the retard limiting mechanism contacts a retard-side engaging portion of the engaging groove to limit retard of the relative rotational phase.
However, according to the above phase limiting mechanism, if the distance in the circumferential direction between the two engaging elements is shorter than the distance in the circumferential direction between the two engaging portions, one of the engaging elements does not fit the engaging groove. In addition, when the phase interval between the two engaging elements is longer than the distance in the circumferential direction between the two engaging portions, a clearance is formed between one of the engaging elements and a corresponding one of the engaging portions. If the clearance is too large, collision noise problematically occurs because of a collision between one of the engaging elements and a corresponding one of the engaging portions.